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Questions tagged [rf]

Short for Radio Frequency, i.e. frequencies at which radiation (intentional or not) plays a role. Typically associated with wireless communications, but also relevant for high-speed PCB design.

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High Insertion Loss on 4 Layer 5.8 GHz Board

I've built a board to serve as the front end of a 5.8 GHz Wi-Fi radio. The boards were built using OSH Park's 4-layer service, which uses ISOLA FR408-HR. It seems like these boards should be ...
cEEa's user avatar
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5 votes
1 answer
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If ESR for a capacitor is not given, can you use f, C, and Q to calculate it?

To calculate ESR when it is not given, can you use the \$Q\$ value as follows? According to Wikipedia, dissipation factor relates \$Q\$, \$\text{ESR}\$, and \$\tan(\delta)\$ as follows: $$ \frac{1}{Q} ...
KJ7LNW's user avatar
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-1 votes
1 answer
61 views

Can we use telescopic antenna for RF receivers? [closed]

Can we use TE antenna for receiver? Because I have seen that TE antenna is used in transmitters and for receivers spring coil antenna is used. The reason that I have asked this question is I have seen ...
Saeed's user avatar
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0 votes
1 answer
57 views

Injecting bits to a parallel communication bus possible?

Antennas can recieve data (bits) because RF signals induce an analog signal into it in a serial format, essentially a voltage that varies over time. My question is can we have an antenna that can ...
19216811's user avatar
2 votes
1 answer
68 views

Visualizing 2 Layer PCB Return Currents

Hobbyist moving a manhattan-style prototype of an analog FM radio to a PCB for ease of assembly and access to SMT parts. I have attempted a 2 layer FR4 board with a 1.6mm thickness, as I feel that ...
Yousif Alniemi's user avatar
1 vote
1 answer
68 views

Why do direct conversion receivers amplify only after mixing?

The vast majority of the simple direct conversion receivers I've seen amplify only after mixing. The RF is filtered before mixing, but not amplified at all. For example (from Solid State Design for ...
SRobertJames's user avatar
  • 1,135
2 votes
0 answers
38 views

Unable to replicate Twisted IFA antenna S-parameter curve using ANSYS HFSS 15

I am attempting to replicate the S-parameter curve for an antenna design as described in the paper "Antenna Design and Analysis" with DOI: 10.1109/LAWP.2009.2015345 using ANSYS HFSS 15. Here ...
A R's user avatar
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0 votes
1 answer
56 views

What is the purpose of this table on RF remote controls?

On most of the RF remote controls we can see this table. Can you explain what it means?
Saeed's user avatar
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0 votes
1 answer
50 views

What is the optimal way to place a BNC connection point on a printed circuit board?

I am working on my first RF project and I have two signals coming onto my board through a BNC connection. I have selected this BNC but their data sheet is not very informative. https://www.digikey.com/...
Roderick's user avatar
0 votes
0 answers
13 views

ideal N-port Touchstone spec

Want to specify ideal i.e. frequency independent S-parameter N-port components in Touchstone file (v1 or v2), for import into circuit simulator. The official specs don't mention how many frequency ...
kev01's user avatar
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2 votes
0 answers
31 views

Where should I take the measurement from to find the correct attenuation level of a resistive pi attenuator?

I am currently designing a resistive attenuator for an RF project I'm working on. I wanted to have several resistance combinations to obtain various attenuation levels (1-8 dBs). When I calculate the ...
OpenBrainedProf.'s user avatar
1 vote
0 answers
34 views

BJT Gilbert cell with emitter-degeneration

I am trying to design a Gilbert cell mixer. I am stuck on one requirement. Background: The RF differential voltage swing should above 900mVpp (currently RF=991.2mVpp.) This swing must remain the same....
Tom's user avatar
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0 votes
0 answers
28 views

Modeling a short 10mm wire for RF

This is related to another question of mine looking for parasitics which need to be added to prevent oscillations in simulations . How should I model a short 10nH wire (say AWG 20 with 0.8 mm diameter ...
bobuhito's user avatar
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1 vote
0 answers
54 views

Can this oscillator possibly work?

I am trying to build a crude RF oscillator. My first attempt, though it simulated fine, disappointingly did not oscillate when soldered together. So, to debug this, I reduced the simulation example ...
bobuhito's user avatar
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0 votes
1 answer
45 views

How can I simulate an RF signal as received by an antenna in LTspice?

How can I simulate an RF signal as received by an antenna in LTspice? I am designing a simple HF RF receiver and want to test it via LTspice. Can I simulate an RF signal as: A pure voltage source, ...
SRobertJames's user avatar
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0 votes
1 answer
75 views

RF jammer module power measurement using a spectrum analyzer

I have an RF jammer module that works at 2390-2510 MHz. The voltage is 24-28 V and it can transmit up to 50 W. When I use a spectrum analyzer, the value is around -20 dBm. If I'm not mistaken, -20 ...
Raihan Anwar's user avatar
0 votes
2 answers
89 views

12 channel remote control: 4-pin IC for 12 buttons: How?

This RF remote control uses ev1527 encoder. Although this IC has just 4 pins for buttons, this remote control has 12 buttons. How they have done such thing?
Saeed's user avatar
  • 27
0 votes
1 answer
50 views

Piezo tr switch no echo signal

I set this circuit to use piezo as transceiver. I can perfectly transfer the transmitter signal (10 burst pulse) but as transmitter still connected onto piezo , any reveived signal is disappears. When ...
ali demir's user avatar
1 vote
1 answer
55 views

MICRF112: loop vs monopole antenna

I'm designing a PCB that trasmit over 433 MHz with MICRF112. The datasheet says that the device works with monopole or loop antennas. I decided to go with a monopole antenna. This is the example ...
ocirocir's user avatar
  • 132
1 vote
2 answers
142 views

Will this FM transmitter work?

I found this schematic on circuit digest. I have tried to simulate it in LTspice. That's the wave I got from the simulation. Most of time it's just DC and does not oscillate at all. Is this going to ...
kile's user avatar
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0 votes
1 answer
49 views

How can I slow down the rise and fall time of a power MOSFET without adding a delay before the switching begins?

I'm building a simple 5 W HF CW transmitter, where the power to the final stages is controlled by a P-Channel Power MOSFET, whose gate is connected to a key. I added a simple capacitor between the ...
SRobertJames's user avatar
  • 1,135
-1 votes
0 answers
85 views

30MHz signal that could drive a 100W load

I'm seeking an AC source or signal generator for a RF application with the following specifications: Output bandwidth: 0-30MHz Power output: 100W (necessary for sustaining a plasma) The issue I'm ...
ludicrous's user avatar
  • 1,163
1 vote
1 answer
50 views

Electrically long loop antenna with homogenous near B field inside antenna loop

I wanted to know is it possible to create a loop antenna that functions in a way like a high frequency helmholtz coil. Because a helmholtz coil is usually made with multiple turns of wire having high ...
Girts's user avatar
  • 31
1 vote
2 answers
37 views

RF Microstrip trace polygon

I'm designing a board with an RF L-band trace (around 2.150GHz) on the top layer side. I have a clear and unbroken ground plane on the bottom layer of the trace. However, I'm curious to know whether ...
mehrad aghaei's user avatar
0 votes
1 answer
40 views

P2P communication: maximum range for low power & low bandwidth

I've started a little side project with the goal of tracking my cat's location in real time. To transmit the GPS-data, it seems like I have two options: I can either use cellular communication or (...
bns's user avatar
  • 3
0 votes
0 answers
43 views

Impedance matching T/R switch

I do drive a piezo as transceiver. My transmitter provides square burst around 10Vpp which is too big for simply switching through a diode by dc biasing. I found out that bridge rectifier structure ...
ali demir's user avatar
-1 votes
1 answer
75 views

Active RF signal repeater

I have two stations, A and B. Station A broadcasts a pure 10MHz sinusoidal signal on air. A ...
epsi1on's user avatar
  • 101
2 votes
1 answer
102 views

Telecom Lines Conducted emissions noise travel

I am seeking an explanation of how conducted emissions on telecom lines are measured. The frequencies of interest are at 150kHz to roughly 850kHz. The size of the unit is 30cm by 30cm by 15cm. The ...
DRF's user avatar
  • 536
0 votes
1 answer
83 views

What is inside of a typical RF transformer?

I am tempted to decap this 500 MHz transformer, but guessing the internals are typical and well-known by experts here. I don't understand why many companies don't even spec the two windings' DC ...
bobuhito's user avatar
  • 554
-2 votes
1 answer
66 views

Transmitter parasitic drainage [closed]

I have a RF cordless calling/alarm bell which works on batteries. The receiver works with 3x AA batteries and its transmitter works with a 23A (12v) battery. The product works with their function. The ...
Kokachi's user avatar
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0 votes
0 answers
64 views

Regarding the voltage in the resonant circuit of a Class F amplifier

When checking the operation, the secondary resonant circuit discharges. When I checked with ADS, I confirmed that the voltage was not high enough to cause a discharge at 150V or less. Regarding the ...
kimura's user avatar
  • 11
1 vote
0 answers
67 views

Guidance on development of FM radio [closed]

I am in the process of learning all about FM/AM and already have managed to make my own working transmitter. All these are some starting steps in order to make my own FM radio. Regarding that, I would ...
Gregory Kafanelis's user avatar
1 vote
0 answers
14 views

Creating a short signal transmission in HT12E based RF communication

In HT12E we continuously transmit even when the input data pins are not changed.My problem is battery optimisation. I am transmitting only ON/OFF switch state through HT12E based RF module and Since ...
Anandhan A's user avatar
0 votes
1 answer
48 views

S-parameters of a matching network

I have the following matching network designed for \$\omega=2\pi\cdot 1GHz\$ and I want to calculate \$S_{11}\$ and \$S_{21}\$. The normal definitions/calculation setup for S11 that I use are in the ...
Halleff's user avatar
  • 675
0 votes
0 answers
51 views

Vacuum tube amp RF plate choke design

I am building a vacuum tube RF power amplifier for SSB. Here is the link for the amplifier. https://www.qsl.net/vu2awc/ham_radio_india_v/vu2atn_qro/vu2atn.htm I need to clarify first that I am ...
Ashok Das's user avatar
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-1 votes
0 answers
50 views

Embedded device with Hardware issues consisting atmega 328p, RFM96 and ADXL345

I have a device that works on 3V battery (2 D size cells) now I want to debug it so that all the devices work correctly. My device consist of atmega 328p, running on 08 MHz Crystal which gets readings ...
Talha Ashfaq's user avatar
-2 votes
1 answer
73 views

Cranes operating on 433 MHz remotes experience shutdown [closed]

I have in operation multiple cranes with hoists and bridges. The system seems to experience single hoist shutdown when two remotes on 433 MHz operate together. There are six remotes available. The ...
Wing's user avatar
  • 1
0 votes
2 answers
75 views

Where to find/learn standard meaning of ω or φ, etc., in RF circuit design

I am retired from a long career in Electronic Warfare (EW) in the US Navy, followed by decades in communications in two-way radio engineering, cellular system technical management, etc, and then a ...
Dale's user avatar
  • 103
0 votes
2 answers
63 views

Question About Utility Company Antenna Power/Radiation Concerns [closed]

Removed due to personal data, thanks
VWjetta's user avatar
1 vote
2 answers
85 views

How to sample current in high-kHz to low-MHz [closed]

I am working on a project that, at its simplest, is a switching circuit (either a half-bridge or single switch) connected to a resonant filter. I need a way to measure/sample the current going from ...
Joshkoz16's user avatar
0 votes
0 answers
33 views

Can transceivers count to fifty resonators? [duplicate]

I asked a since-closed question yesterday about an alternative to RFID. I assumed the way to phrase the question was as the most general possible engineering problem. I infer that it is probably ...
Tom Boardman's user avatar
0 votes
0 answers
21 views

OBD2 Pwr+Gnd causes poor GPS reception in device plugged into it, looking for causes & solutions

Myself and a few others have built a custom device (PCB & components) which is designed to run while plugged into an OBD2 connector in a vehicle and capture GPS location data and transmit it via ...
bgp's user avatar
  • 273
0 votes
0 answers
42 views

Why the loop bandwidth must be much smaller than the input frequency to ensure settling behavior?

Razavi said, in Section 9.6 Loop bandwidth of his book RF Microelectronics that In the design of PLLs, we impose... a loop bandwidth much smaller than the input frequency to ensure a well-behaved ...
Tong Su's user avatar
  • 113
3 votes
1 answer
87 views

Why wouldn't one use a DAC for an RF transmitter?

I'm wondering what would be the reasons that someone would use something other than a DAC to generate IF signals before they're mixed up to RF. With how fast modern DACs can be (30 MSPS from some ...
Arthur Prudius's user avatar
0 votes
1 answer
71 views

Generating Sinewave with PLL [closed]

I'm trying to make a sine wave and sweep frequency near 150MHz. Since my application requires exact frequency and high stability, I'm trying to look for a PLL. However, I cannot determine if the chip ...
KYLee's user avatar
  • 11
3 votes
1 answer
355 views

Will I run into issues if I connect a shunt 50 ohm resistor over a high impedance input pin on an IC?

I am using a level shifter with high impedance input pins. The input to the shifter is coming from a 50 ohm output impedance component through a 50 ohm line. For matching purposes and according to the ...
Roderick's user avatar
1 vote
2 answers
68 views

How can a Class E Power Amplifier be built and experimented with safely?

Given that Class E RF amplifiers, even those that generate less than a few watts, can easily generate voltage spikes approaching (or exceeding) 100 V, how can they be homebrew built and experimented ...
SRobertJames's user avatar
  • 1,135
0 votes
0 answers
32 views

Finding old rf components datasheets

I've just received a load of old rf components used for X-W band and am at a loss for where to find information on them. A lot of the parts are from TRG division of Alpha Industries Inc. and it seems ...
DTBolt's user avatar
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1 vote
0 answers
33 views

How to match RF transmitter (EV1527) and receiver (SYN470) together?

I have a transmitter that uses EV1527 encoder IC in 433 MHz. Here I want to make a receiver by SYN470. In this case, I am amateur and I do not know how to match transmitter and receiver together in a ...
Saeed's user avatar
  • 27
-1 votes
1 answer
80 views

Are there any LTspice models for OP AMPS with GHz bandwidth? [closed]

I would like to try experimenting with op amps to use as buffers for oscillators. I know op amps exist for such applications because I have found them but none of them have LTspice models. Let me know ...
the_circuit's user avatar

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